This invention pertains to a tube extracting apparatus, and more particularly to an improved tube extracting apparatus for extracting tubes from different types of structures, such as condensers, evaporators, and the like.
For example, a typical condenser generally comprises a pair of parallel tube sheets, a plurality of baffle plates, and a plurality of heat exchange tubes The tube sheets are located at the ends of the condenser, and the baffle plates are positioned between the tube sheets and generally parallel thereto. The heat exchange tubes extend between the tube sheets and through the baffle plates, and are supported by the tube sheets The tube sheets and baffle plates have a series of aligned holes formed therein, and the heat exchange tubes are inserted through these holes and then expanded in the areas of the tube sheets into fluid-tight pressure contact therewith.
Because of malfunctions or normal preventive maintenance, it may be necessary to remove one or all of the tubes from the structure, and this is generally accomplished by first relieving the pressure forces between the tubes and the tube sheets and then longitudinally pulling the tubes through the baffle plates and the tube sheets. Various types of devices are used to initially relieve or break the secure connection between the tubes and tube sheets, and then another apparatus is used to withdraw the tubes from the structure. Generally, these latter apparatuses for withdrawing the tubes are hydraulic jacks, which are slow and require the operator to attach, unattach and then reattach the jack to the tube as it is being withdrawn; or pneumatic devices which are relatively large and heavy, and thus difficult to use in the generally confined spaces containing the various types of structures described above. Another means for withdrawing the tubes from the structure is by manually pulling the tubes through the baffle plates and tube sheets. Naturally, this is a difficult and time consuming task, particularly since the tubes in some cases may have lengths of up to seventy feet and be of considerable weight.
In some cases, the structure, such as a condenser, includes oppositely disposed waterboxes having relatively long depths from which the tubes must be extracted. In these cases, it can be very difficult to maneuver the prior art tube pulling devices into the waterbox to initially grasp and then withdraw the tube. This problem becomes particularly acute if the initial apparatus used for breaking the connection between the tubes and tube sheets does not initially pull the tube far enough from the tube sheet.